Positive psychology constructs such as positive affect, meaning and purpose, and self-efficacy represent domains of human functioning that are inherently valued by cancer patients and survivors, significantly associated with better health outcomes, and unique from the influence of distress and dysfunction. Recent systematic reviews and meta-analyses highlight the importance of psychosocial interventions to reduce negative effects such as depression, pain, and fatigue in patients with cancer, but we lack similar analyses of the potential unique benefits of interventions to promote and sustain well-being. As more people survive and even thrive with cancer, understanding positive adjustment and growth in cancer is an important complement to understanding impairment, disability and psychosocial morbidity in cancer prevention and control research. The objective of this study is to provide a comprehensive summary and meta-analysis of interventions that enhance positive affect, self-efficacy, and meaning and purpose as primary or secondary outcomes and to identify those that have been optimally beneficial for patients with cancer. We propose three specific aims: (1) To obtain, a current, comprehensive, and robust estimate of the effectiveness of psychosocial interventions to promote positive psychological outcomes (positive affect, self-efficacy, meaning and purpose) among cancer patients and survivors, (2) To determine whether the effects of psychosocial interventions to promote positive affect, meaning and purpose, and self-efficacy differ by the type of intervention (education- or skills-based approaches), (3) To examine the relationship between intervention design (study quality based on the Physiotherapy Evidence Database criteria) and patient sociodemographics (sex, age, education, race/ethnicity) as moderators of the strength of the relationship between psychosocial interventions and positive affect, meaning and purpose, and self-efficacy. Three teams of researchers will develop and apply standardized search strategies, systematically reviewing four electronic databases to identify randomized controlled trials meeting selection criteria. Standardized coding schemes will be applied to each study, and individual effect sizes will be calculated and pooled to compare pre- and post-randomization outcomes. Subgroup analyses will be performed to examine moderators of effects. Results will identify the utility of interventions to promote positie psychological outcomes among cancer patients and survivors, advancing support for the importance of positive psychology-based interventions in promoting better health and well-being among patients with cancer.